Load increment switch

SUBSTANCE: switch comprises selector to select winding tap to be reswitched and load switch with at least one tap of current circuit and at least two auxiliary current taps; in each of them in load switch operating both with vacuum circuit breakers and switching cells, besides selector contacts, there are auxiliary switches connected in series with them and the respective winding tap, and in stationary mode the above auxiliary switches perform complete galvanic interruption of vacuum circuit breakers.

The invention relates to a switch of load steps for a seamless switching of the winding branches of a stepped transformer.

Speed transformers known for many years; previously, they had to switch of load steps were mechanical contacts who worked in oil, nowadays many newer devices have vacuum switches.

The use of vacuum switches for switching of load steps prevents the occurrence of electric arcs in oil, and thus the pollution load switch oil. This ensures that maintenance needs to be done less often.

Switches of load steps with vacuum switches is known in many different schemes with 2, 3, 4, or also with a large number of commuting vacuum switches per phase.

The typical pattern, in this case with three vacuum switches, per phase, is described in DE 10 2007 004 530 A1.

However, in many applications such known switches of load steps with vacuum switches for control of power transformers high strength in relation to the pulse voltage up to 100 kV and above.

Such undesirable impulse voltages, the magnitude of which is in large PT�penalties due to the device step transformer and winding parts between the different levels of branches,
are, on the one hand, the impulse voltage lightning that occur in the network after a lightning strike. On the other hand, there may be also switching impulse voltage caused by unforeseen switching pulses in the controlled network.

In case of insufficient resistance switch of load steps in relation to the pulse voltage in the load branch not conducting the load current, can occur speed intermittent short circuit or undesirable breakdown of ceramics or steam protective screen vacuum switches that not only can cause permanent damage, but, in General, is undesirable.

In many cases, in the calculation of discontinuous intervals, and thus, in particular, and vacuum switches, this leads to an increase of their size, they are guaranteed to be able to withstand the load voltage. Increasing the size is a disadvantage as due to the small installation space, which now have modern instruments, and because of the economy and the availability of such vacuum switches.

From DE 2357209 A and DE 2604334 already know that to combat excessive loads tension load between the branches should provide a protective spark gaps, or varistors, or something, � other;
however, these tools in different cases are insufficient and cannot be deleted or not completely prevent the harmful action of loads the voltage pulse.

Therefore, object of the invention is to prevent increase in the size of the vacuum switches and at the same time to provide a switch of load steps according to the invention the necessary dielectric (breakdown) strength.

This task is solved through the switch of load steps with signs of the first paragraph of the claims. The dependent claims relate to preferred improved embodiments of the invention.

The General inventive idea is to offset describes the load voltage vacuum switches on contact device installed in series with them. After a successful shutdown or switch - depending on the scheme - with the help of vacuum switches additional contact device according to the invention immediately after that provide through the no-current switching full isolation on potential. Before the next switching of the load, i.e., before the vacuum switches in reverse order through the contact device according to the invention first is on again�connections to potential.

Contact device according to the invention can be in the form of mechanical contacts directly in insulating oil, they can also be implemented in the form of additional vacuum switches or performed by semiconductor technology.

Below the invention is illustrated in more detail in the exemplary embodiments shown in the drawings, which show:

Fig. 1 - scheme of the first switch of load steps according to the invention,

Fig. 2 - the process of switching,

Fig. 3 is a diagram of another switch of load steps according to the invention.

Fig. 1 shows a switch of load steps, load switch which seamless switches between two branches And, In the winding. In the middle shows the electrical circuit conducting steady state load current. It contains the first vacuum switching element MSV and connected in series with it mechanical contact MTF, depending on the switch can connect each of the two branches A or b with the first vacuum switching element MSV. Left and right of it shows both the auxiliary circuit, performing a seamless switching of the load current; they are made with the possibility of including for a short time when switching from�ellenemi and outlet LA load and short time loop current.
They consist, respectively, of an additional vacuum switch TTVAor TTVVand connected in series with them intermediate resistor R.

According to the invention between the connected branches A, b and vacuum switches TTVATTVBthe auxiliary current circuits in series with them included respectively contact SCVAor respectively SCVBthat in a stationary mode as a no-current auxiliary changeover contacts fully electrically disconnects the vacuum switches TTVAor TTVVand performs isolation on potential.

Thus, a simple and effective way to provide reliable protection of these vacuum switches from overvoltage such as surge voltage.

Fig. 2 shows the sequence of action of the load switch according to the invention. It is shown that the SCV contactsAand SCVVprior to the switch install the necessary galvanic connection of the vacuum switches TTVAand TTVVin a corresponding conductive auxiliary branches, and after switching again provide isolation capability in another subsidiary branches.

Fig. 3 shows a modified embodiment of the stipulated�the invention switch load switch load steps.
With no mechanical contacts SCVAand SCVVaccording to the invention is made not as a separate people, and as a relay with changeover contact. Such an arrangement provides a preferred actuation of these contacts, their operation and effect changes nothing.

It should be mentioned that the function of contacts serially connected according to the invention in auxiliary electrical circuit with each vacuum switch, designated in the examples of execution as SCVAor SCVVnot tied to a particular scheme or a number of vacuum switches. In the framework of the invention are possible and recommended many other schemes.

1. Switch of load steps for a seamless switching of the winding branches of a stepped transformer that containsa selector to select without consuming power of the new winding branches that you want to switch,and a load switch for the seamless switching of the loadwherein the load switch comprises at least one main branch of the circuit, which in the stationary regime is conducting a load current from winding connected to the branch before discharge of the load at least one vacuum switch, andmoreover, the load switch further contains at IU�Isha least two auxiliary circuit,
which, respectively, represent the successive inclusion of additional vacuum switch and at least one intermediate resistor and installed, respectively, between one of the winding branches and allotment of the loadwhereinthat, in addition to contacts of the selector, each of the at least two auxiliary branches of the current in the load switch between the corresponding branch (A, b) winding and the corresponding additional vacuum switch (TTVATTVIn) sequentially installed driven separately additional contact (SCVA, SCVB).

2. Switch of load steps according to claim 1, characterized in thatadditional contacts (SCVA, SCVBmade in the form of mechanical contacts in the oil.

3. Switch of load steps according to claim 1 or 2, characterized in thatadditional contacts (SCVA, SCVBmade in the form of a relay with changeover contacts.

4. Switch of load steps according to claim 1, characterized in thatadditional contacts (SCVA, SCVBmade in the form of additional vacuum switches.

5. Switch of load steps according to claim 1, characterized in thatadditional contacts (SCVA, SCVBmade in the form of semiconductor �Hemi or semiconductor circuits.

SUBSTANCE: tap changer with semiconductor switching elements is intended for uninterrupted changing between winding taps of a step transformer; it is made as a hybrid switch comprising fixed mechanical contact fingers and opposed contacts installed at a movable contact bracket. Semiconductor switchover units are intended for load transfer, they are switched by means of contacts at the contact bracket when load is transferred in a specified switching sequence.

EFFECT: development of the tap changer featured by the simple design and high operational reliability, which can be used for switching of different step transformers without forced special-purpose matching to the transformer.

SUBSTANCE: invention relates to the method of detecting of malfunction of the vacuum breaker in a live tap changer in which the tap changer contains a housing filled with oil, a diverter switch comprising a mobile contact (MC, RC) and, at least, one vacuum breaker (MVI, RVI) designed with a possibility of interruption of the current passing through the mobile contact of the diverter switch. The method includes the repeating stages during which the content of hydrogen in oil is determined and the existence of malfunction of the vacuum breaker (MVI, RVI) is identified on the basis of measurement of the content of hydrogen in oil.

EFFECT: decrease of risk of false identification of malfunction with an immediate emergency shutdown of the transformer.

SUBSTANCE: invention refers to a drive mechanism. A drive mechanism for a medium voltage fuse switch comprises a base plate (10) and a front plate (11) which form an inner space enveloping a working shaft and a driving shaft set coaxially along the first longitudinal axis, the driving shaft is functionally coupled with a kinematic circuit of the medium voltage fuse switch, the working shaft (20) is fitted by a head connected to an operating handle for manual actuation of the working shaft, a spring unit consisting of two spiral springs having the first end functionally coupled with the working shaft, a clamping unit consisting of two clamping tabs set on the driving shaft, the first (61) and the second (62) unclamping units to unclamp the driving shaft and provide for its rotation. The first unclamping unit (61) provides for the rotation of the driving shaft in the direction opposite to the second unclamping unit (62).

SUBSTANCE: invention is related to an on-load tap charger with semiconductor switching elements for uninterrupted switching between fixed contacts of the tap charger which are connected electrically to the tapped winding of the tapped transformer. Each of the fixed contacts of the tap charger can be connected to the device for charging either directly or through interconnected semiconductor switching elements. According to the invention the tap charger has separated and fixed tapping contacts for electric insulation of the semiconductor switching elements from the transformer winding during the static mode of operation.

EFFECT: excluding high load of switching elements and guaranteeing electrical separation of the tap charger from the transformer winding in the static mode of operation.

SUBSTANCE: tap changer for a transformer comprises a cylinder and a shaft which is rotatably arranged inside the cylinder. The cylinder is provided with fixed contacts and the shaft is provided with a contact circuit facing the cylinder and including mechanical contacts, wherein the mechanical contacts are adapted to selectively mate with the fixed contacts of the cylinder upon rotation of the shaft. The contact circuit also includes at least two measuring points for measuring the characteristics of the contact circuit. The tap changer comprises at least one measuring contact device, which is electrically connected to the respective measuring points in the contact circuit. The measuring contact device is placed inside the shaft.

EFFECT: wider field of use of the tap changer and the measurement method by facilitating access to measuring points of the tap changer.

SUBSTANCE: invention relates to a manual drive for stepwise control of a step transformer winding tap changer with a locking device, without power consumption. Besides, there is a master shaft, on which per one change there are several manual rotations implemented. There is also a control mechanism, which converts these rotations exactly into one rotation of a geared wheel per one change. The locking mechanism comprises a rotary inner key and a latch rotating around the axis of rotation and a stop, which corresponds to the stop slot of the master shaft, and a stop cam, which corresponds to the slot of the geared wheel of the control mechanism. Due to actuation of the inner key, the latch rotates from the locked position so that the stop and the stop cam are disengaged from the appropriate slots.

EFFECT: higher reliability of protection in respect to undeliberate or deliberate incorrect usage of a manual drive.

SUBSTANCE: invention is designed for changing taps in power transformers. A modified diverter switch comprises mechanical and electric interface, compatible with a switch body, main and intermediate contacts, a holder of current-limiting resistance comprising an interface coupled with the body of the available tap changer for provision of modification of the diverter switch, besides, multiple modules of current-limiting resistances may be connected together. The diverter switch may comprise a vacuum switch and may be installed in a body of the available tap changer.

EFFECT: invention provides for simple tuning of a diverter switch to user requirements for various use and possibility to modify an on-load tap changer.

SUBSTANCE: in several horizontal planes around rotating switching axis on insulating frame, fixed contacts are located. These contacts contain upper and lower contact fingers which are released and closed by electroconductive bus as moving switching contact.

SUBSTANCE: compartment (2) of the electric motor within the on-load tap changer comprises an electric motor module and a control module (12). The module of the electric motor comprises an electric motor (6), a reducer (7) and a position sensor (9), besides, the control module (12) is made with the possibility to control an output shaft (3), which goes out from the compartment (2) of the electric motor, by means of power supply to the electric motor (6) via a direct connection to put the output shaft (3) in motion via a reducer (7), besides, the position sensor (9) is made with the possibility to register motion and positions of the output shaft (3) and to transfer information about such to the control module (12). The compartment (2) of the electric motor in the working condition is tightly closed with the electric motor module and the control module (12), arranged inside such tightly closed volume.

EFFECT: reduced time for production deployment, increased flexibility for making changes into the order at the later stages of its completion, increased convenience of service, reduced cost of the electric motor for the on-load tap changer.

SUBSTANCE: high-voltage semiconducting switching device consists of selected by leakage current series connected unpackaged semiconducting elements that are centred and isolated by side surface with the help of fluoroplastic rings, housing, clamping system and current-carrying electrodes. The housing is made of isolating material with high mechanical and electrical strength. At both housing ends there are rigidly fixed metal flanges that are included in clamping system with threaded holes. At bolting of switching device cover to housing flanges with the help of clamping system elements located inside the cover there created is necessary compressive force of semiconducting devices and its transmission through the housing to semiconducting devices. Note that at the same time there performed is pressurisation of inner volume of switching unit housing by O-rings located between flanges and current-carrying electrodes.

EFFECT: increase of specific switching power of high-voltage semiconducting switching device current at simultaneous improvement of its switching characteristics.

SUBSTANCE: invention suggests energy accumulator with offsetting mechanism and on-load regulator comprising energy accumulator having simple and inexpensive construction, which may suppress load moment to ensure stable operation. Offsetting mechanism in-built to energy accumulator comprises protruding part 8, thrust 9 and offsetting camp 17. The protruding part is fixed to the bottom part of eccentric cam 2. Thrust 9 is fixed to the end of protruding part 8. Offsetting camp 17 is shaped as isosceles triangle giving apex angle equal in essence to 90 degrees and fixed to the top part of body part 5 that accumulates energy. Offsetting camp 17 coming in contact with thrust 9 through accumulated energy of body part 5 makes crank 6 rotating and moves latch 7 to stand-by position.

SUBSTANCE: in transformer winding taps switching unit the transformer is made with two branches of the split winding with low- and high-voltage taps, thyristors are joined into two valve groups with opposite conductivity directions and interconnected by two outputs, with a phase lead of the supply circuit. The valve group with one conductivity direction is coupled but its other outputs to taps of one branch of the split winding while the valve group with opposite conductivity direction is coupled to the other branch of the split winding.

SUBSTANCE: invention is related to an on-load tap charger with semiconductor switching elements for uninterrupted switching between fixed contacts of the tap charger which are connected electrically to the tapped winding of the tapped transformer. Each of the fixed contacts of the tap charger can be connected to the device for charging either directly or through interconnected semiconductor switching elements. According to the invention the tap charger has separated and fixed tapping contacts for electric insulation of the semiconductor switching elements from the transformer winding during the static mode of operation.

EFFECT: excluding high load of switching elements and guaranteeing electrical separation of the tap charger from the transformer winding in the static mode of operation.

SUBSTANCE: invention is related to electrical engineering and can be used in distributing mains in order to decrease voltage fluctuations. The transformer contains a stepping switch on the basis of one or several mechanical switches. At switching current is directed through semiconductor switches in order to ensure uninterrupted operation.

SUBSTANCE: tap changer for a transformer comprises a cylinder and a shaft which is rotatably arranged inside the cylinder. The cylinder is provided with fixed contacts and the shaft is provided with a contact circuit facing the cylinder and including mechanical contacts, wherein the mechanical contacts are adapted to selectively mate with the fixed contacts of the cylinder upon rotation of the shaft. The contact circuit also includes at least two measuring points for measuring the characteristics of the contact circuit. The tap changer comprises at least one measuring contact device, which is electrically connected to the respective measuring points in the contact circuit. The measuring contact device is placed inside the shaft.

EFFECT: wider field of use of the tap changer and the measurement method by facilitating access to measuring points of the tap changer.

SUBSTANCE: invention is referred to electric engineering and can be used for supplemental reactivity of an arc furnace transformer. Reactive ballast arrangement (V) for the arc furnace consists of a choke coil (1) with an open switch (2) for load increment changing which is suitable for installation of the choke coil (1) reactance under load. Reactive ballast arrangement (V) is connected before the transformer of the arc furnace (O) used, in particular, for steel making.

SUBSTANCE: invention relates to a manual drive for stepwise control of a step transformer winding tap changer with a locking device, without power consumption. Besides, there is a master shaft, on which per one change there are several manual rotations implemented. There is also a control mechanism, which converts these rotations exactly into one rotation of a geared wheel per one change. The locking mechanism comprises a rotary inner key and a latch rotating around the axis of rotation and a stop, which corresponds to the stop slot of the master shaft, and a stop cam, which corresponds to the slot of the geared wheel of the control mechanism. Due to actuation of the inner key, the latch rotates from the locked position so that the stop and the stop cam are disengaged from the appropriate slots.

EFFECT: higher reliability of protection in respect to undeliberate or deliberate incorrect usage of a manual drive.

SUBSTANCE: invention relates to a transformer winding stages switch with semiconductor switching elements for continuous switching between the two branches (branch n, branch n+1) of winding of a transformer with staged voltage control each winding branch is connected to the common load output via the corresponding mechanical switch (DS) and a series circuit of two oppositely placed IGBTs (IP, In), the circuit linked in series to the mechanical switch. According to the invention, each IGBT is shunted with a corresponding varistor (Vp, Vn), connected in parallel thereto and calculated in a special way.

SUBSTANCE: invention relates to the method of breakless switching between two taps (tap n, tap n+1) of a transformer winding with stepped voltage control, besides, each of both winding taps via an appropriate mechanical switch (DS) and a circuit arranged subsequently with it from two opposite IGBT (Ip, In) may be connected with a common loading outlet.

SUBSTANCE: proposed stepping thyristor switch has mechanical stepping selector and load switch. Stepping selector only is disposed in transformer oil tank while load switch incorporating thyristors is mounted in separate case attached to one side wherein it is held in air medium, so that switch thyristors are disposed away from hot transformer oil.